Dan, thank you and I don't mean to sound ungrateful, but if you could try that again in laymans terms? I might have a clue what you said LOL As I said at the top I know little about FPV so you lost me after "Hmm..."
sorry liemavick. really didn't mean to geek out. I'll assume you understand the nature of PFM, to know I ain't got it covered either, but:
taking a step back to the early chapters in an RF book, skipping all the gain stages and directionality, polarization of an omni-antenna comes in 4 basic flavors. horizontal(H), vertical(V), left circular(L), right circular(R). now you loose signal strength in a myriad of ways, but having mis-matched antenna polarizations is a really easy way to throw away signal.
Theoretically H-H, for example would have no loss, or 0dB, but a H-V would completely loose the signal -- more practical RoT is -20 to -30dB or 100 to 1000 times quieter. Now what's the difference between a V and an H? whether the antenna is pointing up or on the side. so twist your airplane and you go from great signal to nothing. The neat part about a circular (and why we use them) is when they're matched to another circular (R-R, L-L) there is virtually no loss in the signal, no mater how you orient them. another neat property is that a circular is a fair match to a linear -- a L-V, L-H, R-V, R-H only drop -3dB, or 1/2 the signal (I know, dB is a weird scale). So they're always a fair match regardless of orientation -- handy.
The downside - a L-R is ALWAYS a bad match. Again RoT is -20 to -30 dB loss, just from picking the wrong antenna.
Ok, ears bleeding yet?
how it applies -- if you put a L circular on your router and your device is:
H or V - you'll never loose the fair polarization match from how the signal bounces, but the antenna could have been better if it was an exact match -- loose a little range.
L - great match anywhere -- full range!
R - terrible match -- Poor range.
My *Guess* is you'll have a more consistent signal on H or V antennas (or diverse antennas using H & V elements) because reflection/smear effects, out where the signal is weak, have less effect. I'd also *Guess* it would be shorter range because the match could be better.
